Because dropping copper into concentrated HCl should do absolutely nothing interesting, per the Standard electrode potential ( data page ), which clearly shows that the E o of Cu + 2H +-- > Cu 2 + + H 2 to be-. 340 V . Either you're providing some excess energy somewhere, or its simply not going to do anything.
32.
The standard electrode potential E 0 against standard hydrogen electrode ( SHE ) is 0.230V ?10mV . The potential is however very sensitive to traces of bromide ions which make it more negative . ( The more exact standard potential given by an IUPAC review paper is + 0.22249 V, with a standard deviation of 0.13 mV at 25 �C .)
33.
The polarity of the standard electrode potential provides information about the relative reduction potential of the electrode compared to the SHE . If the electrode has a positive potential with respect to the SHE, then that means it is a strongly reducing electrode which forces the SHE to be the anode ( an example is Cu in aqueous CuSO 4 with a standard electrode potential of 0.337 V ).
34.
The polarity of the standard electrode potential provides information about the relative reduction potential of the electrode compared to the SHE . If the electrode has a positive potential with respect to the SHE, then that means it is a strongly reducing electrode which forces the SHE to be the anode ( an example is Cu in aqueous CuSO 4 with a standard electrode potential of 0.337 V ).
35.
Due to the high standard electrode potentials of both zinc and cerium redox reactions in aqueous media, the open-circuit cell voltage is as high as 2.43 V . Methanesulfonic acid is used as supporting electrolyte, as it allows high concentrations of both zinc and cerium; the solubility of the corresponding methanesulfonates is 2.1 M for Zn, 2.4 M for Ce ( III ) and up to 1.0 M for Ce ( IV ).
